Microwave plasma burner

ABSTRACT

A microwave plasma burner in which a high temperature plasma is generated. The microwave plasma burner includes a wave inducing tube for receiving and guiding microwaves from an antenna of a magnetron within a wave guide resonator, so as to generate a high temperature plasma by causing vibrations of an injected gas by the help of the microwaves while discharging the injected gas. The microwave plasma burner according to the present invention gives the following effects. A strong high temperature plasma can be generated with a structure not involving vacuum. The flames are generated by the heat which is generated by the vibrations of air, and therefore, a separate igniting device is not required. High temperature flames are generated, and therefore, the burner of the present invention can be used for welding and cutting. A complete combustion occurs due to the heat which is generated by the vibrations, and therefore, any air pollution can be prevented. A desired gas can be selected, and therefore, any oxidation can be prevented during a welding.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a microwave plasma burner in which ahigh temperature plasma is generated.

2. Description of the Prior Art

Microwaves belong to a frequency region of 30 MHz to 30 GHz, andmicrowaves are widely applied to various apparatuses such as microwaveoven and the like. Particularly, microwaves are utilized in generating aplasma.

In the plasma, the gas is highly ionized, and positive ions and negativeions are present in the same magnitude of density. Thus electricalbalance is realized, and a neutralization is attained. The glowdischarge tubes and the arcing columns are the typical examples.

Conventionally, in order to generate a plasma by utilizing microwaves, ahigh vacuum is formed in a chamber, and then, a gas or a gas mixture isinjected into the vacuum chamber. The microwaves are irradiated into thechamber.

Then a plasma is generated within the chamber.

However, in this conventional method, a high vacuum is formed within thechamber into which microwaves are irradiated. In order to form the highvacuum, a precise design is required and therefore, the actualmanufacture becomes very difficult.

Further, in a welding burner, an igniting device is needed, andtherefore, an inconvenience is encountered during the use.

BRIEF SUMMARY OF THE INVENTION

The present invention is intended to overcome the above describeddisadvantages of the conventional technique.

Therefore it is an object of the present invention to provide amicrowave plasma burner in which a high temperature plasma is generatedby guiding microwaves without forming a high vacuum.

It is another object of the present invention to provide a microwaveplasma burner in which an igniting device is eliminated for ensuring theconvenience.

In achieving the above objects, the microwave plasma burner according tothe present invention includes: a wave inducing tube for receiving andguiding microwaves from an antenna of a magnetron within wave guideresonator, so as to generate a high temperature plasma by causingvibrations of an injected gas by the help of the microwaves whiledischarging the injected gas.

Further, the microwave plasma burner according to the present inventionincludes: a magnetron for outputting microwaves through an antenna; awave guide resonator for resonating the microwaves from the antenna; andan inducing tube installed within the wave guide resonator, forreceiving and guiding the microwaves from the antenna to causevibrations of an injected gas so as to generate a high temperature heatand a high temperature plasma during a discharge of the injected gas.

BRIEF DESCRIPTION OF THE DRAWING

The above objects and other advantages of the present invention willbecome more apparent by describing in detail the preferred embodiment ofthe present invention with reference to the attached drawings in which:

The drawing illustrates the constitution of the microwave plasma burneraccording the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The drawing illustrates the constitution of the microwave plasma burneraccording to the present invention.

As shown in this drawing, the microwave plasma burner according to thepresent invention includes: a wave inducing tube 210 for receiving andguiding microwaves from an antenna 110 of a magnetron 100 within a waveguide resonator 200, so as to generate a high temperature plasma bycausing vibrations of an injected gas by the help of the microwaveswhile discharging the injected gas.

The inducing tube 210 has a size proportional to that of the antenna110, and has the same contour as that of the latter. Particularly, thepart of the inducing tube 210, which is disposed within the wave guideresonator 200, has the same shape as that of the antenna 110, and has asize twice as large as the antenna 110.

That is, the microwave plasma burner according to the present inventionincludes: a magnetron 100 for outputting microwaves through an antenna110; a wave guide resonator 200 for resonating the microwaves from theantenna 110; an inducing tube 210 installed within the wave guideresonator 200, for receiving and guiding the microwaves from the antenna110 to cause vibrations of an injected gas so as to generate a hightemperature heat and a high temperature plasma during a discharge of theinjected gas to an end portion 211; a guide tube 320 for surrounding theinducing tube 210 to focus the heat (generated from the end portion 211of the inducing tube 210); and an outer electrode tube 330 forsurrounding the guide tube 320, for preventing the dissipation of themicrowaves (released from the end portion 211 of the inducing tube 210).

The inducing tube 210 has a size proportional to that of the antenna110, and is made of a conductor such as copper or the like.

The guide tube 320 focuses the high temperature flame, and therefore,should be made of a heat resistant insulating material such as quartz orthe like. The outer electrode tube 330 is made of a rigid conductivematerial such as a stainless steel.

A part 220 of the inducing tube 210, which is disposed within the waveguide resonator 200, is made of a non-conductive material such as aceramic, so that there would be no conduction between the inducing tube210 and the wave guide resonator 200. A housing 400 which accommodatesthe magnetron 100 and the wave guide resonator 200 is made of steel, sothat the housing 400 can serve as a grounding means, and that themicrowaves would not be leaked to the outside. A part 410 which is thecontacting portion between the housing 400 and the inducing tube 210 ismade of a non-conductive material. A guide 350 which supports theinducing tube 210 to the outside of the housing 400 is made of anon-conductive material, so that any conduction to the inducing tube 210would not occur. A securing member 340 which is disposed on the outsideof the guide 350 so as to secure the guide tube 320 and the electrodetube 330 is made of a conductive material.

The part 410 which is the contacting portion between the housing 400 andthe inducing tube 210 is made to be contacted to the securing member340.

Further, the magnetron 100 generates much heat, and therefore, in orderto release the generated heat, there is installed a fan 120 to carry outan air cooling.

The microwave plasma burner of the present invention constituted asabove will now be described as to its operation.

If a power is supplied to the magnetron 100, then microwaves aregenerated. The generated microwaves are supplied through the antenna 110to the wave guide resonator 200 so as to be resonated.

The microwaves which are resonated within the wave guide resonator 200are guided by the inducing tube 210 to the end part 211.

If a gas is supplied into the inducing tube 210, then the gas isdischarged along the inducing tube 210 to the end part 211.

The gas which is being discharged to the end part 211 of the inducingtube 210 is vibrated by the microwaves which are guided along thesurface of the inducing tube 210. During this process, a hightemperature heat is generated, and due to the generated heat, flames 500are produced. Depending on the injected gas, the temperature of the endpart 211 becomes different. Particularly, in the case where theatmospheric air is injected, the temperature of the flames of the endpart 211 becomes about 3,000 degrees C.

Further, a plasma 600 is formed around the flames 500.

Meanwhile, the guide tube 320 which surrounds the inducing tube 210focuses the generated flames, while the outer electrode tube 330prevents the microwaves from being released to the outside.

Thus owing to the high temperature heat, the flames 500 are generated atthe end part of the inducing tube 210. Under this condition, dependingon the kind of the discharged gas, the temperature of the heat becomesdifferent. Therefore, in accordance with the needs, the kind of the gascan be selected.

For example, during a welding, in accordance with the properties of thewelding material, the temperature can be varied. That is, in order toprevent an oxidation and to raise the temperature, one gas can beselected suitably from among nitrogen, carbon, and argon.

Further, in the case where the atmospheric air is injected into theinducing tube 210, a high temperature heat and a plasma are generateddue to the vibrations of the microwaves.

Under this condition, the flames are automatically generated at the endpart 211 of the inducing tube 210 due to the vibrations of themicrowaves, and therefore, a separate igniting device is not required.

According to the present invention as described above, the microwaveplasma burner according to the present invention gives the followingeffects.

First, a strong high temperature plasma can be generated with astructure not involving vacuum.

Second, the flames are generated by the heat which is generated by thevibrations of air, and therefore, a separate igniting device is notrequired.

Third, high temperature flames are generated, and therefore, the burnerof the present invention can be used for welding and cutting.

Fourth, a complete combustion occurs due to the heat which is generatedby the vibrations, and therefore, any air pollution can be prevented.

Fifth, a desired gas can be selected, and therefore, any oxidation canbe prevented during a welding.

What is claimed is:
 1. A microwave plasma burner comprising: a magnetronfor outputting microwaves through an antenna; a wave guide resonator forresonating the microwaves from said antenna; an inducing tube installedwithin said wave guide resonator, for receiving and guiding themicrowaves from said antenna to cause vibrations of an injected gas soas to generate a high temperature heat and a high temperature plasmaduring a discharge of the injected gas; a guide tube for surroundingsaid inducing tube to focus the heat generated from the end portion ofsaid inducing tube; and an outer electrode tube for surrounding saidguide tube, for preventing a dissipation of the microwaves released fromthe end portion of said inducing tube.